Uncatalyzed Three‐Component Synthesis of α‐Hydrazido Phosphonates

Herrera, Raquel P.; Roca‐Lopez, David; Navarro‐Moros, Gloria

doi:10.1002/ejoc.200901337

Cited by 14 publications

(11 citation statements)

References 46 publications

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“…The synthesis of N‐ acylhydrazones 1 a , 1 e , 1 f , 1 l , and 1 n , as well as catalysts 3 c and 3 d , was reached by following the protocols described in the literature. The spectroscopic data obtained of alkyl substituted N‐ acylhydrazones 1 a , 1 e , 1 f , 1 l , and 1 n , catalysts 3 c and 3 d , and hydrazide derivative 4 na are consistent with the values previously reported in the literature. DFT calculations were performed by using Gaussian 16, kinetic simulations to obtain concentration profiles were carried out with Berkeley Madonna…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Organocatalyzed Aza‐Henry Reaction of Hydrazones: Experimental and Computational Studies

Sonsona

Alegre‐Requena

Marqués‐López

et al. 2020

Chemistry A European J

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The first asymmetricc atalyzed aza-Henry reaction of hydrazones is presented. In this process, quininew as used as the catalyst to synthesize different alkyl substituted b-nitrohydrazides with ee up to 77 %. This ee wasi mproved up to 94 %b yafurther recrystallization and the opposite enantiomer can be obtained by using quinidinea st he catalyst, opening exciting possibilities in fields in which the control of chirality is vital, such as the pharmaceutical industry. Additionally,e xperimental and ab initio studies were per-formed to understand the reaction mechanism. The experimental resultsr evealed an unexpected secondary kinetic isotope effect (KIE) that is explained by the calculated reaction pathway, which showst hat the protonation of the initial hydrazone and the CÀCb ond forming reaction occur during a concerted process. This concerted mechanism makes the catalysis conceptually different to traditionalb ase-promoted Henrya nd aza-Henry reactions.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.Scheme2.Catalysts tested in the asymmetricaddition of nitromethane(2a)t oN-acylhydrazone 1a.DCM = dichloromethane; n.r. = no reaction;n.d. = not determined; rac. = racemic mixture;r .t. = roomtemperature.Scheme4.Proposed catalytic cycle for the asymmetric organocatalyzed addition of nitromethane 2a to hydrazones 1.

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Section: Methodsmentioning

confidence: 99%

Asymmetric Organocatalyzed Aza‐Henry Reaction of Hydrazones: Experimental and Computational Studies

Sonsona

Alegre‐Requena

Marqués‐López

et al. 2020

Chemistry A European J

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“…After the pioneering chiral organocatalytic example appeared in 1983, 10 in which a scarce number of aldehydes (only two) was disclosed, requiring successive recrystallizations to improve the enantioselectivities, only a pivotal example of an organocatalysed approach has been published in 2009 by Ooi's group. 11 Our experience in the organocatalysed Pudovik reaction with imines 12,13 and hydrazones, 14 and the lack of background information on aldehydes encouraged us to explore the feasibility of catalysing this process with hydrogen bonding based catalysts, due to their well-known capacity to activate carbonyl compounds. 15,16 In this communication, we report our appealing results concerning the first asymmetric squaramide-organocatalysed Pudovik reaction using aldehydes.…”

Section: Scheme 1 Direct Approach To Appealing Phosphonate Derivativesmentioning

confidence: 99%

Organocatalytic enantioselective hydrophosphonylation of aldehydes

et al. 2014

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We report our results concerning the first squaramide-catalysed hydrophosphonylation of aldehydes. In all cases, the reactions proceeded smoothly and cleanly under mild reaction conditions rendering final α-hydroxy phosphonates in very good yields and high enantioselectivities. It is one of the few organocatalytic examples of this reaction using aldehydes. It is the first time that diphenylphosphite (1e) has been successfully employed in a chiral Pudovik reaction with aldehydes, in contrast to the dialkylphosphites used in previously published procedures, extending the generality of this asymmetric methodology.

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“…The lack of reactivity and the dramatic descent of the reaction rates using these dialkyl 60 phosphites (6b-e) might be due to the drastic variation of its pK a values, [20] as we observed in a previous work. [21] Having established the optimal reaction conditions, we further explored the scope of this 1,4-Michael addition for various substituted nitroolefines 5b-l. Corresponding derivatives 7a-l 65 were furnished with very good yields and good enantioselectivities in CH 2 Cl 2 at -10 ºC (Table 4).…”

Section: Fig 3 Bifunctional Mode Of Actionmentioning

confidence: 99%

Thiourea catalyzed organocatalytic enantioselective Michael addition of diphenyl phosphite to nitroalkenes

et al. 2011

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Bifunctional thiourea catalyzes the enantioselective Michael addition reaction of diphenyl phosphite to nitroalkenes. This methodology provides a facile access to enantiomerically enriched β-nitrophosphonates, precursors for the preparation of synthetically and biologically useful β-aminophosphonic acids. DFT level of computational calculations invoke the attack of the diphenyl phosphite to the nitroolefin by the Re face, this give light to this scarcely explored process update in the literature. The computational calculations support the absolute configuration obtained in the final adducts.

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Uncatalyzed Three‐Component Synthesis of α‐Hydrazido Phosphonates

Cited by 14 publications

References 46 publications

Asymmetric Organocatalyzed Aza‐Henry Reaction of Hydrazones: Experimental and Computational Studies

Asymmetric Organocatalyzed Aza‐Henry Reaction of Hydrazones: Experimental and Computational Studies

Organocatalytic enantioselective hydrophosphonylation of aldehydes

Thiourea catalyzed organocatalytic enantioselective Michael addition of diphenyl phosphite to nitroalkenes

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